The three QR's are Classic knob, Fliplock and monobalfix type. The Fliplock is a quick and sturdy QR. But it is designed for our plates or a single manufacturer's plates only. many of the other manufacturers, while making 'Arca-Swiss style' Qr's and plates, did not copy the specifications and so some are wider and a few are even narrower than our plates. So if you buy a mixture of manufacturers plates, you do not want the fliplock. The Classic QR will accept almost all of the Arca-Swiss style plates made and also will accept the new compact series of monobalfix plates in a dual channel design. The knob is captive so won't unscrew and is extremely rugged and sturdy. The Fliplock will also accept the compact monobalfix plates as well. The monobalfix system will accept only the monbalfix plates and is very compact and makes the head a bit lighter as well. These plates are very compact, as is the QR and rigid as well. Totally centered the compact plates will also pan perfectly if pano stitching is in your bag of tricks. We make L brackets and pano kits for both series of QRs as well. Hope this helps. Rod Klukas Arca-Swiss USA Representative